In this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe 3 O 4 @SiO 2 -CT-Co) as a magnetically core-shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki-Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe 3 O 4 NPs core encapsulated by SiO 2 shell, and the size of the particles was estimated about 30 nm. Compared with the previously reported catalysts, the engineered Fe 3 O 4 @SiO 2 -CT-Co catalyst provided perfect catalytic performance for the Suzuki-Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity.